Neo Geo is an interesting system. The graphics system in particular is very elegant for old-school hardware. Like Atari 2600 and Amiga, sprites can be extremely tall at essentially no extra cost; it's the width that really eats up the budget (which on Neo, IIRC, are timeslices on a state machine that renders the sprites into a linebuffer, rather than physical FIFOs). Unlike Atari 2600 and Amiga, the hardware has the concept of "chaining" sprites so that a huge meta-sprite's position can be controlled by a single attribute block. There's no background hardware; the way you build backgrounds is by creating huge sprites. The hardware also has a simple mechanism for automatic animation so that various kinds of environmental animation can be done without the CPU having to update all of the pattern numbers.

There is a textmode-like foreground layer (the "fix" layer, probably called that because it can't scroll) for UI elements like score, credits, life meters, etc..

Trivia: Neo Geo was not primarily designed by SNK, but rather by Alpha Denshi (ADK), presumably acting as a contractor. It bears some similarities to earlier boards for ADK and SNK games (see the MAME drivers "alpha68k" and "snk68").